The treatment of wounds in mammals, both animals and humans, has historically involved a simple passive bandage which provides physical protection and, to some extent, reduces infection. The treatment has progressed from this simple bandage to more active treatments. In serious wounds, particularly burns, skin grafting and skin sheets have been applied. Eventually the skin cells "take" and fill in the wound.
Attempts have been made to expedite healing by introduction of various growth factors directly into the wound, see Brown G. L., Curtsinger L., Jurkiewicz M. J., Nahi F., Schultz G., (1991) "Stimulation of Healing of Wounds by Epidermal Growth Factor," Plast. Reconstr. Surg , Vol. 88, pp. 189-194; Brown G. L., Nanney L. B., Griffen J., Cramer A. B., Yancey J. M., Curtsinger L., Holtzin L., Schultz G., Jurkiewicz M. J., and Lynch J. B. (1989).
"Enhancement of Wound Healing by Topical Treatment with Epidermal Growth Factor," New England J. Med., Vol. 321, pp. 76-79; ten Dijke P., Iwata K. K., "Growth Factors for Wound Healing" (1989) Biotechnology, Vol. 7, pp. 793-798; Pierce G. F., Mustoe T. A., Altrock B. W. Deuel T. F., Thomason A., (1991), "The Role of Platelet Derived Growth Factor in Wound Healing Cellular Biochemistry," Vol. 45, pp. 319-316; and, "EGF and PDGF-Alpha in Wound Healing and Repair," Schultz Rotatori and Clark, J. of Cellular Biochemistry, Volume 45, pp. 346-352 (1991).
Growth factors encourage the proliferation and/or differentiation of the cells in the tissue within and around the wound. Several attempts have been made to introduce these growth factors into the wound by means of a topical gel or the like, applied over the surface of the wound. However, such growth factor containing gels have several drawbacks. The amount of growth factor contained in these gels is fixed. Over time, the enzymes produced from the patient's own tissue may degrade the gel and/or the growth factor. Further, the isolation and purification of the growth factor may decrease its biological activity.
Attempts nave been made to drip the growth factor directly into the wound. However, this method of application is not continuous and does not provide a uniform amount of arowth factor to the different areas of the wound.
In addition, many growth factors have a short half life, thus the amount of growth factor delivered to the wound substantially decreases with time. Finally, the cost of the isolated, purified growth factors is extremely high.
While the addition of growth factors to wounds has accelerated wound healing, the above drawbacks have prevented widescale use of the growth factors in wound treatment.
Thus, it would be desirable to have a bandage that could continually supply biologically active growth factors in uniform amounts directly to wounded tissue.